Melting copper-lead



Patented May 23,

- UNITED STATES PATENT OFFICE nonnar n.

ma, ornmnno, canroimm, nssrcnoza 'ro mm conrona'rron, or mm, camronma, a conronarron or DELAWARE 1 min-me corrnn-rmn Io Drawing. Application-filed August 18, 1931,

The present invention relates to aprocess for obtaining mixtures of copper and lead either the molten state or in the solid state, wherein the metals are thoroughly in- 5 termixed so 'that articles may be cast or otherwise made therefrom of uniform composition throughout. Attempts have hitherto been made to produce thorough mixtures of these metals, but lo this has always involved the addition of other elements or materials, such for example, as other metals or sulphur, and es- 7 pecially when the proportion of lead in the copper-lead metal ran from about thirty to fifty percent of-the whole, the added ma terials generally being retained in the composition. I have found that the relatively preparation of a molten mixture of copper and lead having ,'the same composition throughout the mass thereof.

Another objectof my invention-is the pre- 0 paration of a molten mixture of copper and lead having a uniformcomposition throughout the mass thereof so that that part of the mass poured first will have the same'composition as'that part of the mass poured last.

Another obfject' of my invention is the 49 preparation 0 mixtures of copperand lead which do not contain foreign substances.

. Another object of my invention is the pre paration of a bearing metal consisting es sentially of '00 per and lead wherein the lead content'may die as high as fifty percent of the whole. 1

Another object of my invention is the preparation of a bearing metal consisting of sixty percent of copper and forty percent of lead. 3 I

copper and lead rapidly to become thorough- -ble, and it is to be understood that any Serial 1105551947. Renewed January 18, 1933.

Another object of theinvention isthe pre'paration of various articles including bear-- ing surfaces consisting of copper and lead in varying proportions wherein the lead may be the minor ingredient 'or equal to half of the whole mixture and wherein the compo sition of the article 'made is uniform throughout or may be controlled. I

Another object ofthe invention is to cause ly mixed in the liquid state so that castings containing any desired proportion of lead up to fortypercent of the whole or even fifty percent of the whole, the balance being copper, can. be made of substantially: unvarying composition;

Other objects of the invention will be 1 come apparent on reading the appended description.

vLead and copper are practically immiscibleiin' the solid state'but they are complctely miscible at equilibrium in all proportions when in the liquid state above 1900 F. In practice, however, it has been very difiicult to arrive at such equilibrium since the greater part of the lead tendsv to remain in the lower. part of the melt, so that castings made by pouring such metal into a mold or by cast-welding such metal against and onto a'solidmetal, which may be 'a backing of iron or steel or other suitable material, vfary in composition at different points there- In the followin I shall describe a specific process of melting together cop' er and lead for obtaining my novel res t of a rapid and thorough intermixture of the ingredients, it being understood, however, that considerable variations in detail and changes may be made without departin g from the essence of'my invention, my preferred practice being as follows: g I-prefer to melt in crucibles, but electric furnaces of the arc type are also practicasuitable type of melting device is within the spirit of my invention. When using a crucible I first heat it to about 180.0. F. and then place in the bottom thereof one and one-half grams of cupric oxide (0110) for 100 each. poundof metal in the mixture when finally completed, this corresponding to about one-third of one percent of cupric oxide with respect to the entire melt.

On top of this copper oxide I place the total amount of lead required in pigs, this, of course, melting very rapidly. I next cover the molten lead with a protective flux which is made up of a mixture of borax and some earthy substance, such as shale or clay. The preparations of the borax and earthy substance should be so chosen that the flux will be fluid and afford a complete covering for the complete allow when the same is molten, but no determinate composition can be given, since this will vary with the type of earthy substance. It is desirable to have the earthy substance present in the flux,

since borax attacks the crucible rather rapidly, the presence of the earthy substance in the flux reducing this to a degree dependent on the amount thereof present and on the composition thereof. For heating a two hundred ,pound melt, I preferably employ from eight and one-half to ten and one-half pounds of such flux.

In commercial operation there is always .a certain amount of scrap metal resulting from previous pours and the like, and such copperlead scrap may be added, and preferably is so added, along with the new or un-leaded copper. I prefer as a matter of shop practice to use the copper-lead scrap in the form of small pigs or briquettes, and these are put into the crucible containing the copper oxide and the molten lead and flux, whereupon there is added as much of the new or unleaded copper, which is preferably of electrolytic grade, as is required for the melt or as much as may be safely placed in the crucible.

I prefer to maintain a neutral to reducing atmosphere and I also prefer not to force the melting too strongly, sincethis may have a. bad effect on the metal, as by gassing the metal if there is too much flame, or otherwise. When the copper and copper-lead scrap have been melted down, the crucible charge is completed, if not already complete, by the addition of the proper amount of copper or copper-lead scrap, or both.

Heating of the crucible may, of course, be continuous except for possible interruptions for charging it, as may be convenient.

temperature before casting and with this in view the contents of the crucible are brought to a temperature of about 2100 to 2200 F.; the flame is shut off,'the crucible removed from the furnace, and the flux is thickened by the addition of sand, and removed with a graphite stirring rod, leavin a thin protective covering of thickened ux from beneath which the metal is poured while an operator holds back the flux with a suitable skimmer.

In this manner I am able to pour castings and to make cast weldings so that the retion apparently facilitating the mixing of' the copper and lead in the molten state so that the molten mass will be practically of uniform composition throughout. Apparently, lead oxide is dissolved in or in some way carried by the molten lead, and my theory of a partially oxidized molten lead is based "on my discovery that good results may be obtained when the copper oxide may be replaced by. an equivalentamount of lead oxide, and also since good results may also be had without the addition of any metal oxide, if the molten lead be first slightly oxidized by suitable exposure. The process, however, is facilitated by the addition of copper or lead oxide, and of these I prefer the copper oxide. I assume that such copper oxide reacts promptly with the superhot lead to produce metallic copper and lead oxide.

The cupriferous material, that is, the electrolytic copper or the copper lead scrap, which is placed in the crucible on top of the molten lead melts slowly, and as it trickles down it immediately becomes thoroughly mixed with the lead which I believe to be partially oxidized. When the melting has been completed, the crucible contains a thoroughly mixed melt of copper and lead without the necessity of stirring. It is to benoted, however, that if the copper is melted first and the lead dropped into the melt, no

amount of stirring willresult in a meltwhich is of uniform composition throughout and thefirst castings out of the crucible contain as littleas ten percent of lead...

liaving thus described my invention, what I claim and desire to secure by LettersPatent is: Y

1. The process of making uniform mixtures of copper and lead, which comprises The metal is brought to a good casting adding molten metal of the class consisting of copper and copper-and-lead to molten lead at a temperature above the meltin point of copper and containing lead oxide.

lead. i 6. The process of uniforminixtures of copperand lead, which com rises,

melting lead in the presence of an oxi 'zing' agent t9 obtain a small amount of oxide therein, and meltingthereinto metal of the class consisting of copper and copper-andtures of copper and lead, which comprises melting lead in contact with a smallamount of copper oxide, and melting thereinto metals of the class consisting of copper and copper-and-lead. r

71 The process of making uniform. mixtures of copper and lead, whichcomprises melting into super-heated molten lead containin lead oxide metal of the class consist-r ing. of copper and copper-and-lead. V

8. The process of m uniform mixtures of copper and lead, which comprises mixing molten copper with molten lead which contains lead oxide and which is at about the-melting point of the copper.

9. The process of making uniform mixtures of copper and lead, which comprises placing lead in acrucible of morganic material which is at a' temperature of about 1800 F. and which contains an amount of a material of the group.consisiting of copper oxide and leadsoxide uivalent to about oneand'one-half grams 0 cupric oxide foreach pound .of metal in the mixture whenfinally completed, coverin the molten mass with a protective flux, ad dingsolidcopper thereto and melting the copper. a

10. The process of makin uniform mix- 'ch comprises terial which is at. a temperature of about 1800 F. and which contains an amount ofa material of the group consisting of copper oxide and lead oxide equivalent to about one and one-half grams of cupric oxide for each pound of metal in the mixture when finally completed, covering the molten mass with a protective'flux of borax and siliceous earthy substance, adding solid copper thereto and melting the copper. I

11. .The process of making uniform mixtures of copper and lead, which comprises placing the total amount'of lead required as pigs in a crucible of inorganic material which is at a temperature of 1800 F. and which contains an amount of a material of the group consisting of c'opperoxide and lead oxide equivalent to about one and one half grains of cupric oxide for each pound of metal in the mixture when finally com pleted, covering the molten mass with a promixing mo tective flux of borax and siliceous earthy material, adding copper pigs and any previously made copper-lead scrap thereto, and

melting the copper and scrap.

12. The process of making uniform mix tures of copper and lead, which comprises placing the total amountof lead required as pigs in a crucible of inorganic material which is at a temperature of 1800 F. and which contains an amount of a material of the group consisting of copper oxide and lead oxide equivalent to about one and onehalf grams of cupric'oxide for each pound of metal in the mixture when finally completed, covering the molten mass with a protective flux-of borax and siliceous earthy material, addin cop er i s and an reviously made c pper lead s%rap thereiiin melting the copper and scrap, heating the metal to about 2100 to 2200 F. thickening the flux with sand, removing rod, and pouring the metal from beneath the remaining thin layerof thickened flux.

' 13. The process of'making uniform'mixtures of copper and lead, which comprises melting into super-heated molten lead contamlng lead oxide metal of the class'consisting of copperr and copper-and-lead, the amount of said lead oxide being equivalent to about one and one-half. grams of cupric most of it with a oxide for each pound of metal in the. final 1 product.

. 14;. The process "ofmaking uniform mixtures of copper and lead, which comprises I ten copper metal with molten lead which is at a temperature at least as high as the melting point of the copper metal, the amount of .said lead oxide to about one and one-half grams of cupric oxide for each pound of metal the final product.

15. The process of making uniform mixtures of copper and lead, Which=comprises heatmg lead together with an amount of a material of the group consisting of copper oxide and lead oxide equivalent to about one and one-half grams of cupric oxide for each pound of metal in the final product, covermg the molten mass with a protective flux, adding solid copper thereto copper. V

16. The process of making. uniform mixtures of copper'and lead, which comprises 'heating lead together with an amount of a material of the group consisting of copper oxide and lead oxide, equivalent to about one and one-half grams of cupric oxide for each pound of metal the final product, covermg the molten mass with a protective flux of borax and siliceous earthy substance, adding solidcopper thereto and melting the copper.

17. The process of making uniform mixtures of copper and lead, which comprises contains lead oxide and which being ,equivalent' and melting the heating lead together with an amount of a material of the group consisting of copper oxide and lead oxide equivalent to about one and one-half grams of cupric oxide for each pound of metal in the final product, covering the molten mass with a prote'tive flux of borax and Vsiliceous earthy material, adding copper pigs and any previously made copper-lead scrap thereto, and melting the copper and scrap.

18. The process of making uniform mixtures of copper and lead, which comprises heating lead together with an amount of a material of the group consisting of copper oxide and lead oxide 'equivalent'to about one and one-half grams of cupric oxide for each pound of metal in the final product, covering the molten mass with a protective flux of borax and siliceous earthy material,

adding copper pigs and any previously made copper-lead scrap thereto, melting the copper and scrap, heating the metal to about 2100 to 2200 F., thickening the flux with sand, removing most of it with a. rod, and pouring the metal from beneath the remaining thin layer of thickened flux.

ROBERT D. PIKE. 

